1. Field of the Invention
The present invention relates to a communication system for transmitting and receiving enhanced text and graphics with commercial FM radio broadcasts; and more particularly, to a radio communication system wherein the enhanced text and graphics are displayed in color on the face of a radio receiver.
2. Description of the Prior Art
The Radio Data Systems (RDS) was developed in Germany in the 1980s as an outgrowth of a traffic alerting system. It is widespread throughout Europe, and was introduced into the US in 1993 where it is known as Radio Broadcast Data System (RBDS). In 1997, numerous automakers introduced RDS radios in the US. RDS uses a low data rate digital subcarrier at 57 kHz to transmit data such as a station""s call letters or program type (Jazz, etc.) along with the main radio signal. The data rate is 1187.5 bits per second, equivalent to a 1200 baud modem, although after overhead and mandatory protocol elements are accounted for the remaining data rate available to applications is about 300 bits per second. There is also a provision for sending 32 or 64 character text messages, referred to as xe2x80x9cRadio Textxe2x80x9d. The data is typically displayed on a small monochrome text screen mounted on the radio""s face. Most commonly, this screen is 8 characters long, and Radio Text messages are scrolled across the screen to present the entire message.
The RBDS standard is created and published by the National Radio Systems Committee (NRSC), formed jointly by the National Association of Broadcasters (NAB) and the Consumer Electronics Manufacturers Association (CEMA), a division of the Electronics Industry Association (EIA). The RBDS standard is a derivative of the RDS standard published by the European Broadcasting Union, headquartered in Geneva, Switzerland, as CENELEC EN50067.
The RDS data stream consists of 16-bit blocks called A, B, C, and D, which are transmitted sequentially in endless repetition. Each block carries a specific data type, which is defined by the RDS protocol. The A block always carries the radio station ID, B-blocks contain control information, the C block carries either station ID or data, and the D-blocks contain data. Each specific arrangement of A, B, C, and D blocks is called a group, of which there are 32 types, divided into 16 type A groups, and 16 type B groups. The RDS and RBDS standards define specific meanings or applications for several of these groups, while several groups remain unused and undefined. The first four bits of the B block defines to the group number of the possible 16 groups within a group type, and the next bit defines if it is a group type A (bit 5=0) or a group of type B (bit 5=1). Group types are referred to with the notation 0A, 0B through 15A, 15B. The distinguishing character of group type B is that the station ID from the A-Block is duplicated in the C-block of the group, making this slot unavailable for data. In the US, the station ID serves no purpose.
The Group Type determines the application, and thereby the definition of all the variable bits in the B-Block. Only one or two applications can be defined by an individual Group Type, that matter being determined by whether the C- and D-Blocks will be used for the same application, or whether the C-Block will carry one application while the D-Block will carry another. As an example, the Group 0A has two applications, one in which the C-Block carries Alternate Frequency information, and one in which the D-block carries Program Service information (also called Slogan).
Two individual bits in the B block are used for highway traffic announcement related indicators (the TP bit, and the TA bit). The TP bit assignment is common to all group types, while the TA bit assignment is only defined in three of the group types. In the prior art, the B block was configured as described in FIG. 2.
Several deficiencies and proposed solutions of the present arrangement of RDS/RBDS are described in co-pending U.S. patent application Ser. No. 60/115072 filed Jan. 7, 1999 entitled Enhanced Radio Data System, the entire disclosure of which is incorporated herein by reference thereto. The present invention, Enhanced Radio Graphics Data System, is a significant enhancement over RDS that can work in companionship with the improvements shown in Ser. No. 60/115072. One of the deficiencies described in Ser. No. 60/115072 relates to the RDS feature of Radio Text. Radio Text is implemented in application groups 2A and 2B. The Radio Text feature of Group Type 2A transmits a text stream of 64-characters; the Group Type 2B version of Radio Text transmits a 32-character text stream. The data transmitted by either version is a monolithic chunk, meaning the receiver treats it as a single chunk of 32-characters, or a single chunk of 64-characters. In addition, the protocol allows no identification as to what the data being carried represents. In other words, the data could be a string of asterisks, a message like xe2x80x9cWelcome to WQXR New York""s Classical Radio Stationxe2x80x9d, a phone number, or any other piece of information. The receiving radio has no way to tell the nature of this data or how to use it. The data can be displayed, and nothing else. An additional limitation of Radio Text is that it does not support presentation information describing how the information is to be display on a screen. An accompanying limitation of RDS is that, due to the extremely limited availability of control bits in the B-Block, it does not support the transmission of the large amounts of data necessary to create color graphic information representations.
The Enhanced Radio Graphics Data System incorporates a color graphics protocol enhancement of RDS. This new protocol, which is backward compatible with RDS i,=3j- receivers, enables RDS to transmit data such as xe2x80x9cArtist and Title,xe2x80x9d xe2x80x9cComing Next,xe2x80x9d DJ names, advertisements, phone numbers, etc. in color and different text styles (bold, italic, etc.) and sizes for presentation on a color display screen. The Enhanced Radio Graphics Data System receiver comprises an FM receiver, RDS demodulator and decoder, a color display, microprocessor and memory.
The present invention is a significant benefit to radio listeners in that it allows the listener to know what is playing, the artist and title, and other information about the music, station, DJ, etc., and that such information can be presented in an appealing fashion on a color graphic display screen.
The present invention is a significant benefit to radio broadcaster in that it allows the broadcaster to display on a radio: a) station call letters; b) tag lines, such as xe2x80x9cClassic Rock of the 80""s and 90""sxe2x80x9d; c) phone numbers; artist and title; d) xe2x80x9cComing Nextxe2x80x9d announcement; e) advertisement messages; and f) station promos in color and different text styles and sizes.
The present invention, referred to herein as xe2x80x9cEnhanced Radio Graphic Data Systemxe2x80x9d, represents a significant improvement over RDS. The Enhanced Radio Graphic Data System affords enhancements over both RDS and RBDS. As used herein, the term xe2x80x9cRDSxe2x80x9d is applied in a generic fashion to mean both RDS and RBDS transmission standards and receivers. Where there might be a difference between the U.S. and European standards, the term xe2x80x9cRBDSxe2x80x9d is used to refer specifically to the U.S. standard.
The Enhanced Radio Graphic Data System incorporates a protocol enhancement of RDS involving the redefinition of several bits within the B-block as illustrated in FIG. 3, with an accompanying arrangement utilizing data in the C- and D-Blocks to create message streams containing the text data to be presented along with associated formatting instructions, as illustrated in FIG. 4.
Broadly stated, from an end-to-end system perspective, the invention provides an Enhanced Radio Graphic Data System comprising the same transmission and receiver elements as today""s RDS and RBDS. These transmission and receiver elements comprise: (i) a generating means for generating a carrier wave at a first predetermined frequency and a subcarrier wave at a second predetermined frequency; (ii) an encoding means for coding the text; (iii) a first modulation means for encoding the subcarrier with the text data generating an encoded subcarrier; (iv) a scheduling means for scheduling the encoding of the subcarrier wave at predetermined intervals; (v) a summing means for adding the audio signal and encoded subcarrier thereby generating a summed signal; (vi) a second modulation means for encoding the carrier wave with the summed signal thereby generating a modulated carrier wave containing both audio signal and text data; (vii) a transmission means for transmitting the modulated carrier wave; (viii) a receiving means for receiving the modulated carrier wave; (ix) a decoding means for decoding the audio signal and the text from the modulated carrier wave; (x) storage means for storing decoded text; (xi) a display means for displaying the text messages; and (xii) an audio signal playing means.
The invention also provides a method for encoding color graphics and text messages into a commercial radio transmission. Generally stated, the method comprises the steps of: (i) storing into memory a text message and graphics bits, the graphics bits indicating the size, style, and color of said text message; (ii) generating a subcarrier of the carrier frequency of the radio transmission; (iii) segmenting the text message into text segments and along with the graphics bits into blocks of binary data; (iv) assembling the blocks into groups of four blocks each, the groups comprising a data stream for transmission; (v) encoding the groups with control bits, the control bits indicating the beginning and end of the text segments, and the number and location in the data stream of the text segments that comprise a complete message; (vi) modulating the subcarrier with the data stream; and transmitting the modulated subcarrier as part of said carrier frequency.
Like RDS receivers, the Enhanced Radio Graphic Data System receiver comprises an FM receiver, RDS demodulator and decoder, display, microprocessor and memory.